The present invention relates to an apparatus for removing the outermost sheet of material from a stack of such sheets and, more particularly, relates to an apparatus in a photofinishing station for removing the outermost envelope from a stack of envelopes and presenting that envelope for subsequent handling.
The apparatus will be described in terms of an envelope feeder in a photofinishing station, for which the apparatus is particularly well suited, but it should be understood that the apparatus can also be used to feed other sheet materials in other environments.
In the photofinishing industry, a customer's film is delivered to a processing lab in an envelope bearing customer identification. The film is removed from the customer envelope for processing, and the customer envelope is retained. Typically, the developed film and prints made therefrom are funneled to an operator station for reinsertion into the used envelope for return to the customer. Since labs tend to process a large quantity of film, individual customer envelopes, film, and prints are maintained in corresponding sequential order for correct matching by the operator. To maximize efficiency, it is desired that corresponding envelopes, film, and prints be automatically presented one by one to the operator. Typically, customer envelopes are queued in a stack at the operator's station, and then separated and presented by a high-speed feeder.
Sheet feeders have been developed that grip the outermost sheet with a high-friction or suction gripper, and then slide that sheet off the stack of sheets. However, these feeders do not work well for feeding used customer photo envelopes, since the envelopes are wrinkled and tend to interfere with each other, making sliding separation difficult. In addition, some envelopes may contain adhesive, tape, or staples that tend to bind adjacent envelopes together, making sliding seperation even more difficult.
This difficulty has been partially overcome by sheet feeders that grip the outermost sheet and then peel that sheet from the stack. However, such feeders tend to fail to separate customer photo envelopes that are adhered together, and generally feed sheets at a rate that is too slow for the photofinishing industry.